1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a design for a plasma display panel that can improve light emission efficiency while lowering power consumption by placing the discharge electrodes around individual discharge cells and mounting a resistive element on the discharge electrodes that are used to initiate discharge.
2. Description of the Related Art
A plasma display panel (PDP) is a flat panel display device that displays characters and images. A potential difference is applied to electrodes causing an electric field in a discharge cell that produces a plasma. The plasma generates ultra violet radiation that excites a fluorescent layer in the discharge cell to produce visible images.
A surface discharge type PDP includes discharge sustaining electrode pairs that include X and Y electrodes formed on an inner surface of a front substrate, a front dielectric layer that covers the discharge sustaining electrode pairs and a protection film coated over the front dielectric layer. Also, address electrodes run in a direction that crosses over the discharge sustaining electrode pairs. A rear dielectric layer covers the address electrodes, barrier ribs are formed on the rear dielectric layer and fluorescent layers of red, green, and blue are coated on the walls of the barrier ribs and on the inner surface of the rear dielectric layer. When the front substrate and the rear substrate are coupled together, discharge cells are formed. These discharge cells are filled with an inert plasma gas.
To drive a PDP having the above structure, discharge cells are selected by applying electrical signals to a Y electrode and an address electrode that cross at the selected discharge cell. Then, electrical signals are alternately applied to the X and Y electrodes thus producing the plasma and the ultraviolet radiation. The ultraviolet radiation then excites fluorescent layers in the discharge cell to produce red, green and blue visible light.
Japanese Patent Laid-Open No. 2004-39601 discloses a structure with improved light emission efficiency, in which scan electrodes are coated with a thin dielectric layer, sustaining electrodes are coated with a thick dielectric layer, and address electrodes are coated with a thick dielectric layer. Japanese Patent Laid-Open No. 2002-184318 discloses a structure of a main electrode for improved brightness, in which main discharging is induced at a reduced discharge current. Japanese Patent Laid-Open No. 1999-344936 discloses a structure that does not require chip resistance for controlling a current input to a PDP. Japanese Patent Laid-Open No. 1998-208646 discloses a structure that can control the reduction of sustaining discharge voltage margin due to non-uniform thickness of a dielectric layer.
However, a surface discharge PDP is a display device using discharge initiation and diffusion in a discharge gap between discharge sustaining electrodes. In this structure of a PDP, brightness depends on how transparent the front substrate is to visible light generated from the excitation of the fluorescent layer by ultra violet rays generated through discharge in a discharge cell. Therefore, the surface discharge PDP has the following drawbacks. First, the transmittance of visible light is less than 60% since the discharge sustaining electrode pair, the front dielectric layer, and the protection film are all formed on an inner surface of the front substrate and the visible light is required to go through or around all of these elements. Second, light emission efficiency is low since the discharge sustaining electrode pair is formed on an inner surface of the front substrate, which is on the very top of the discharge space. Thus, these electrodes block light and hinder light transmission through the front substrate. Also, these electrodes are far from the address electrodes producing a less than optimized discharge. What is therefore needed is an improved design for a PDP that doesn't block the transmittance of visible light through the front substrate while allowing for an efficient discharge to take place, with less power consumption and improved light emission efficiency.